The Oceans of Pluto

TL;DR

Pluto likely has a long-lived subsurface ocean beneath its icy shell, although its existence has not been directly confirmed. New Horizons revealed mountains, widespread geological activity, surface fractures, and cryovolcanic flows that may be only 100–200 million years old. Pluto may also possess organic building blocks associated with life, but whether life ever emerged remains unknown. Read on to see how each clue supports the ocean hypothesis.

Transcript

For most of my life as a space enthusiast there were planets in the solar system that we had not visited. I well remember at age fourteen watching the first visit humanity had ever made to the planet Neptune with Voyager 2 in 1989. Here was a planet that had been discovered in 1846 that we had never seen close up. After that there remained one plan... Read More

Key Insights

• 🥮 The discovery of tholins on Pluto's moon Charon suggests the presence of organic materials necessary for life to arise.
• 🥶 Ice volcanoes and ongoing cryovolcanic activity indicate the existence of a subsurface ocean on Pluto.
• 🛟 The potential for life on Pluto and other icy bodies in the solar system expands the chances of habitable environments and the emergence of life beyond traditional planets.
• 🛟 The discovery of Asgard archaea and the origins of complex life provide insights into the evolution of eukaryotes and the likelihood of complex life in the universe.
• 🥶 Intelligent life may be rarer due to the presence of ice shell environments that do not favor the development of intelligence.
• 🎑 Ecosystems on ice shell moons and planets could be diverse and unique, potentially home to various alien organisms and adaptations.
• 🎑 The abundance of ice shell moons in the solar system suggests a greater chance for habitable environments and life than previously known.

Questions & Answers

Q: Does Pluto have an ocean beneath its surface?

Evidence suggests that Pluto still has a liquid-water ocean beneath its icy surface, though it has not been directly observed. Relatively recent cryovolcanism, surface stretching, and possible reorientation of Pluto’s crust all point to a mobile, nearly frictionless layer below.

Q: What did New Horizons reveal about Pluto?

The New Horizons flyby revealed a dynamic world with varied geography, mountains, and evidence of widespread geological activity. These observations overturned the earlier view of Pluto as a dead ball of ice and rock.

Q: What evidence suggests that Pluto has ice volcanoes?

New Horizons data revealed a network of dome-forming structures and terrain consistent with cryovolcanic flows. The flows lack impact craters in some areas, indicating geologically young surfaces and suggesting that eruptions occurred relatively recently.

Q: When did Pluto’s observed ice volcanoes erupt?

The cryovolcanic features discussed in the transcript appear to have erupted between 100 and 200 million years ago. The process may happen again, which supports the possibility that Pluto remains internally active.

Q: What would erupt from Pluto’s cryovolcanoes?

The eruptions could involve molten water mixed with ammonia or methane, producing a slushy or paste-like lava. This material could briefly flow across the surface before rapidly freezing into dome-like formations.

Q: Why do Pluto’s surface fractures support the subsurface-ocean theory?

Pluto’s fractures appear consistent with stretching of the surface, which could be caused by an ocean moving underneath. Cracks of widely varying ages, extending back toward Pluto’s ancient history, suggest that this internal activity may have persisted for a long time.

Q: Why are the tholins on Charon important to the possibility of life on Pluto?

The reddish material at Charon’s north pole contains tholins, organic molecules that form without life but may serve as ingredients for life. Gases from Pluto’s atmosphere can escape and deposit material on Charon, which orbits about 12,000 miles above Pluto’s surface.

Q: Could life exist in Pluto’s subsurface ocean?

Pluto may have organic building blocks and a long-lived ocean that could potentially support microbial life, possibly near geothermal vents on the ocean floor. Whether life actually emerged there is unknown, and the ocean is expected eventually to freeze as radioactive materials in Pluto’s core decay and its internal heat dwindles.

Summary & Key Takeaways

• Pluto, once thought to be a boring, dead ball of ice and rock, revealed a dynamic world with mountains and evidence of geologic activity during the New Horizons flyby in 2015.

• The discovery of tholins, organic materials, on Pluto's moon Charon suggests that Pluto and its moon may accurately represent a double planet and have the necessary building blocks for life.

• Recent findings of ice volcanoes on Pluto's surface and ongoing cryovolcanic activity indicate a subsurface ocean and the possibility of life.